Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

The rash in infectious mononucleosis is usually diffusely macular. A 15-year-old boy presented to us with high grade fever, sore throat, malaise, body aches, and polyarthralgia. He developed annular, erythematous, and non-scaly eruptions on chest and right arm. Blanching erythema was noted on his trunk. He had bilateral tender cervical lymph nodes, severe pharyngeal congestion, petechiae on soft palate, uvular edema, infraorbital edema, and marginal tender hepatomegaly. Investigations revealed lymphocytosis and activated atypical lymphocytes in the peripheral smear, and positive monospot test. The boy subsequently recovered in one week with total disappearance of his rash. Epstein-Barr virus-related infectious mononucleosis was considered the most likely diagnosis for our patient. To our knowledge, this atypical case is the third reported case of annular lesions in infectious mononucleosis. Dermatologists and other clinicians should be alerted to this special presentation of primary EBV infection.
Which virus can be diagnosed with the monospot test?